Question

write note on ozone hole

Answer 1

The ozone hole that forms above the S. Pole every year in late September-early October was one of the first real indications that CFCs could react with and destroy stratospheric ozone.  The hole is not really a hole in the ozone layer, rather a dramatic but temporary thinning of the ozone layer above the S. Pole and the continent of Antarctica.  The ozone concentration decreases to perhaps 30% of its normal value.
It is unusual to find clouds in the stratosphere because there is very little water vapor there.  It gets very cold above the S. Pole in the winter though and polar stratospheric clouds do sometimes form (they are made from water and other materials). This together with an unusual wind pattern above the S. Pole in the winter are thought to create the ozone hole when the sun returns in the spring.

The ozone destruction reactions are shown in purple above.  Cl reacts with O3to make ClO.  This reacts with O to produce Cl and O2.  The Cl is now available to react again with other ozone molecules.

In green are "interference" reactions.  ClO reacts with NO2 to make ClNO3.  The Cl in this "reservoir" molecule can't react with any more ozone.

Now what happens above the S. Pole in the winter is that the reservoir molecules react on the surfaces of the polar stratospheric cloud particles to make some kind of new compound.  This reaction is shown in orange above.  The new compound HOCl accumulates in the air during the winter.  When the sun reappears in the spring, the UV light splits off all the Cl molecules which react with ozone.  A lot of chlorine suddenly becomes available and the ozone concentration takes a nosedive.

Answer 2

☆Hello friend☆

The excess pollution in Earth, causes hole in Oxone. Depletion of ozone allows direct UV rays to enter in Earth, these UV rays causes skin cancer and along with this excess Carbon Dioxide in atmosphere leads to global warming which leads glacier melt.